Bronsted Analysis of Catalytic Promicuity in Enzyme Models and Model Enzymes
Lead Research Organisation:
University of Cambridge
Department Name: Biochemistry
Abstract
Most biological processes involve the action of enzymes, which are central for explaining the workings of living cells and organisms. However, there is no comprehensive quantitative understanding of enzyme action and our current understanding certainly fails the most severe test, that of producing catalysts with rates that rival natural enzymes. Catalysis is defined as transition state stabilisation. We will apply a tool from physical-organic chemistry, linear-free energy relationships, to characterise these transitions states in catalytic systems that have not just one, but several activities (a phenomenon called 'catalytic promiscuity'). We hope to gain detailed insight into the bond-making and -breaking processes in these remarkable catalysts, to trace the evolution of a catalytic machinery on the basic level of mechanistic chemistry and learn about the nature of their transition states.
Organisations
People |
ORCID iD |
| Florian Hollfelder (Principal Investigator) |
Publications
Avenier F
(2009)
Combining medium effects and cofactor catalysis: metal-coordinated synzymes accelerate phosphate transfer by 10(8).
in Chemistry (Weinheim an der Bergstrasse, Germany)
Avenier F
(2007)
Polyethylene imine derivatives ('synzymes') accelerate phosphate transfer in the absence of metal.
in Journal of the American Chemical Society
Babtie AC
(2012)
Kinetic and computational evidence for an intermediate in the hydrolysis of sulfonate esters.
in Organic & biomolecular chemistry
Babtie AC
(2009)
Efficient catalytic promiscuity for chemically distinct reactions.
in Angewandte Chemie (International ed. in English)
| Description | We have applied physical-organic tools (such as linear free energy relationships, isotope effects and kinetic mechanistic analysis with different substrates and cofactors) to understand catalysts that show promiscuity, i.e. catalyse more than one reaction. This includes enzymes on one hand (i.e. members of the alkaline phosphatase superfamily such as the Pseudomonas aryl sulfatase of phosphonate monoester hydrolase), but also synthetic enzyme models ('synzymes') - all catalyzing a group of hydrolytic enzymes that achieve turnover with substantial second-order rate accelerations (kcat_KM_kw), ranging from 10e7 to as high as 10e19, for the hydrolyses of phosphate mono-, di-, and triesters, phosphonate monoesters, sulfate monoesters, and sulfonate monoesters. These substrates vary in size, charge (0 to -2), reactivity (half-lives from 200 days to 10e5 years under near neutrality.), central atom and reaction transition state. The motivation behind this research is the fascinating question how a catalyst that is normally considered to be efficient, because it is highly specialized for its one native reaction can be good for multiple reactions. Our work addressed the questions • whether the same transition states are catalyzed for both reactions: largely they are, but subtle differences exist • how the cofactor influences the reactivity and the extent of promiscuity: cofactors are crucial and syznzyme models can be activated by the presence of divalent metals such as Zn(2+), Co(2+), Mg(2+) or Ni(2+). Likewise the reactivity and promiscuity of the protein catalysts is determined by the metal ion reactivity (as demonstrated by metal ion exchange) • what factors bring about the relatively high efficiency and how efficiency and selectivity trade-off: on top of high metal ion reactivity, steric factors or positioning of general acid/base catalysts are important |
| Exploitation Route | This grant has lead to the award of a ITN European Network, in which two companies are involved that are interested in phosphate reactivity and molecular recognition. However, the interest is long-term and has not lead to direct commercialisation actvities. The understanding of the mechanistic underpinnings of catalysis is relevant for the biotechnology industry: relaibly generating effiient new enzymes is still an unmet challenge. We are now pursuing directed evolution of the versatile catalysts we have characterised for bioremediation (e.g. removal of toxic nerve gases from teh environment). |
| Sectors | Chemicals,Manufacturing, including Industrial Biotechology |
| Description | European Commission (EC) |
| Amount | £2,535,000 (GBP) |
| Funding ID | ITN 238679 |
| Organisation | European Commission |
| Sector | Public |
| Country | European Union (EU) |
| Start | |
| Description | European Commission (EC) |
| Amount | £2,535,000 (GBP) |
| Funding ID | ITN 238679 |
| Organisation | European Commission |
| Sector | Public |
| Country | European Union (EU) |
| Start | 07/2010 |
| End | 06/2014 |